Wool has been one of the most in-demand textiles since 10,000 BCE and for good reason. It’s a naturally made fabric. Today, the product is cleaned of its oils and flattened with metal so it can be turned into yarn. This textile can be used for carpets, jackets, blankets, saddle cloth, and even insulation to name just a few products. It’s soft and luxurious, so there is no wonder why it’s so popular. You’ve probably never asked yourself, though, “Is wool flammable?”
Wool is classified as a flame-resistant fabric. The textile is flammable, but it has to reach at least 1,058 degrees Fahrenheit, to ignite. The material has high water and nitrogen contents in its cells which means if it did ever catch on fire, once removed from the source of the heat, it would self-extinguish the flame.
This article will share more in-depth information as to why wool is flame-resistant. We’ll cover topics such as what happens when the material burns and whether it can melt. Then we’ll explain what makes different fabrics flammable.
Is Wool Flammable?
Wool is made by shearing the coat off of animals. Many think only sheep produce this material but some of the finest of these fabrics come from camels or llamas. After the material is sheared, it’s cleaned to remove excess oils. Sometimes it’s dyed right after the cleaning process and then it’s referred to as stock-dyed wool.
After cleaning the product, it gets sorted into different grades of fleece. The fleece is then flattened with a big metal machine and threaded into yarn. The material can also be dyed after being spun into yarn.
Wool can catch fire, but because of its cell structure, it will likely extinguish any flame that ignites. The reason this material is easy to dye is that it is naturally hydrophilic. This means it likes water. Its natural water contents make it difficult to catch fire. The fact that it has such a high water content as well as a high nitrogen content makes it difficult to ignite and keep the flame burning.
The material has a high LOI which means limiting oxygen index. In other words, if set aflame, this textile needs mass amounts of oxygen to sustain the flame, otherwise, it will snuff the flame out naturally. So while the textile is flammable, it is one of the safest natural fabrics regarding fire safety practices. If you go camping, a wool sweater is a great choice of apparel around the campfire.
Is Wool Fire Resistant?
Flame-resistant fabrics are materials that can resist ignition except at high temperatures. They are usually made up of synthetic fabrics but can include natural textiles such as wool. Sometimes these materials can also be called inherently flame-retardant and there is not any specific differentiation to these names.
The general consensus is that these textiles will not catch fire unless exposed to incredibly high temperatures. Another description of fire-resistant (or inherently flame-resistant) fabrics is that they can also self-extinguish any flames once removed from the original heat source.
Wool is flame-resistant or inherently flame-retardant, because of its naturally high nitrogen and water content. The material has a cross-linked cell membrane structure that prevents the spread of flames. That is a fancy way of saying that the natural fibers of this fabric will swell when on fire and self-extinguish the flame. It doesn’t need any chemicals to aid it in being non-flammable as it already does all the work itself.
The material is flame-resistant because of several factors. Some of those factors are that the textile will not ignite unless exposed to high temperatures and that this fabric does self-extinguish. The natural qualities of this fabric, such as its thickness and high water and nitrogen content, aid in it being flame-resistant as well. With less air between the strands of the material, less oxygen will feed any potential flames.
Is Wool Fire Retardant?
Fire retardant fabrics are more resistant to flame through chemical processes. Materials like cotton can be treated, so they are more resistant to flame than they naturally would be. Technically inherently fire-retardant materials also fall under the title of fire-retardant fabrics. However, the distinction is that anything that is inherently fire retardant does not need to be chemically treated and is safer overall.
With treated fire-retardant materials there are issues that if improperly cared for, these materials can lose their treatment making them less fire retardant. There is no way to test how well a treatment has held up unless it was to actually catch fire. The other issue is that these textiles can give off harmful chemical gasses if they ever were to catch fire.
As mentioned in the previous section, flame-resistant clothing stops burning on its own accord. These textiles do not need to be treated as they are inherently flame-resistant. Both flame-resistant and flame-retardant materials have high ignition temperatures.
Flame-resistant fabrics are naturally more difficult to ignite whereas flame-retardant fabrics are treated to be more resistant to ignition. Also, flame-resistant fabrics usually catch fire but will self extinguish. Flame-retardant materials are often synthetic and instead of self-extinguishing, they will melt which can cause serious burns.
The United States, as well as many other countries, have rules that certain materials must be fire retardant. Public places such as public theaters, schools, or community halls must have draperies that are fire retardant. Children’s clothing must also have treatments or be inherently fire retardant.
This is to prevent injury in public places or to prevent injury to children. These laws are put in place because of how quickly other fabrics such as cotton, silk, or synthetics can catch fire and burn. This can easily be avoided by using more fire-resistant materials such as wool.
Does Wool Burn?
When wool catches fire, it can burn. Once removed from the source of the heat, it usually will self extinguish the fire. To keep a flame ignited on this material, a lot of oxygen is needed due to its high water and nitrogen contents. Because of this, it is unlikely to burn for long and will then smolder and create dry ash.
Because of how difficult it is for wool to burn, many people who work with fire or near explosives wear it as protective gear. For example, the material is used in personal protective equipment by firemen, the military, and occasionally policemen. People who work in welding use this textile to protect against sparks that can come off their equipment.
The textile is very insulating which makes it hard for heat to seep out from under the fabric or build up inside of it. This helps welders and firefighters alike stay close to a constant temperature while they are exposed to excessive heat. This is incredibly important since being near high temperatures is basically their job description.
What Temperature Does Wool Burn?
Wool may not catch fire until it reaches a temperature of anywhere between 1,058 – 1,112 degrees Fahrenheit or 570 – 600 degrees celsius. Because of its high ignition temperature, it’s difficult for the fabric to catch on fire. Usually, the material will self-extinguish any flame or will smolder before turning it into ash.
At the temperature wool can ignite, it would need a vast amount of oxygen for the flame to burn. Otherwise, it would be snuffed out because of a lack of oxygen. The thickness of this textile makes it difficult for air to get into the fabric and harder for a fire to stay burning. Also, it has cross-linked cell membranes which means that when ignited, the fabric swells which will also cause the fire to extinguish, making it difficult for wool to burn.
Can Wool Melt?
Melting is caused by molecules being exposed to so much heat they speed up so fast that they move past each other forming a liquid. Different elements require different amounts of heat to reach this liquid state.
Fire retardant fabrics melt because of the chemicals used to manufacture them and because of the synthetic fabrics they are made with. These synthetic materials can resist ignition up to high temperatures, but because of their chemical composition instead of turning into ash, they will melt.
Wool cannot melt because it is a natural fabric that is not treated with the same chemicals. When the textile catches fire, it can turn to ash or smolder, but it will never melt. The material naturally contains a lot of water which makes it difficult to reach the heat necessary for melting as well as making it difficult for the fabric to stay lit for very long. Since it contains so much water in it, it cools down any flame that may ignite.
Man-made fabrics like acrylic, nylon, or polyester melt because of the synthetic process they undergo to make them more fire retardant. If these materials caught on fire, not only would they melt but they would also produce harmful chemical gas. This can cause severe burns on any skin the fabric melts onto.
The difference for wool is that if it were to ignite, it would naturally self extinguish. It would not cause further damage by melting onto skin nor would it produce harmful gasses. The self-extinguishing properties of the textile also aid in preventing too much smoke from releasing off the fabric.
Does Wool Produce Smoke?
Wool can produce smoke when burning as well as gas. When ignited, it will swell which aids it when it self-extinguishes a flame. The swelling is what helps to prevent extensive smoke and gas from releasing from the material. It would not be anywhere near as much gas or smoke as synthetic fibers produce. The fabrics that are treated to be fire retardant create more smoke and often release harmful chemical gas when burning.
What Happens When Wool Burns?
When wool ignites, the fabric will curl away from the fire. The textile produces a scent like that of burnt hair or feathers when ignited. It will slowly shrink in on itself and any of the material that has been engulfed in flames would crumble easily upon touch. The part of the fabric that had burned would turn into dark gray-colored ash that is soft and cool to the touch.
How to Keep Wool from Igniting
Some textiles that are lighter with long, loose, or fluffy material will ignite easier. The air in these fabrics feeds any potential flame which makes them more likely to fully ignite when any area of them is exposed to flames.
Wool has natural qualities that protect it from igniting. It’s sort of molecularly engineered, by nature, to protect itself from igniting. This is why if it were to catch fire and burn, it reacts by swelling and releasing water and nitrogen to snuff out the flames.
Its natural defenses do not further the burns or damage to the skin and instead leave a soft ashy residue. The cells that make up this fabric have a cross-linked membrane which is part of the reason the textile will swell when exposed to flames. It also makes the strands of the material naturally thick. This leaves less room for oxygen in the textile and makes it harder for a flame to find air to feed it.
Can you Iron Wool?
Wool can be ironed with caution and patience. Because the fabric is so thick, it may require some time to iron out any wrinkles. When ironing, a low temperature is necessary as well as steam. You should not iron the material with dry heat; it can ruin it.
Also, you should pay attention to the pressure you put on the textile as it’s prone to shrinkage, plus you don’t want to stretch or pull it. This may disrupt its original shape and fit. Other than those concerns, a low temperature with a good amount of steam should make for wrinkle-free fabric.
How Does Wool Compare to Other Flame-Resistant Fabrics?
With the wool’s high burning point, it is incomparable to both natural and synthetic fabrics such as cotton and polyester. This textile isn’t the only one resistant to high temperatures. Children between the ages of nine to fourteen months should have flame-retardant clothing.
Some people have wool allergies, and some can’t afford the cost of it, so other materials besides this textile need to be able to meet flame retardant standards as well. Below is a chart of several fabrics that have high ignition rates and can either be inherently flame-retardant or synthetically treated to be flame-retardant.
|Material||Burning Point (degrees Fahrenheit)||Does it Melt?|
Wool has a higher ignition temperature than Kevlar, the material they use for bulletproof vests. Both are incredibly useful in careers where fire or explosives may be present, and both are fire-resistant fabrics.
The difference in using these textiles in a firefighter’s uniform compared to polyester is huge. Polyester is much more likely to ignite but would also melt onto the skin causing additional severe burns and injury. This is why wool is seen as one of the most beneficial natural materials in the world.
Wool is one of the safest fabrics because of how flame-resistant it is. Any material will catch fire at a certain temperature, but some are better to have around fires. This is why countries have rules regulating how fire retardant certain materials for children or public spaces may be.
Wool is one of the few natural fabrics that are flame-resistant. This, as well as many other qualities, makes it a preeminent textile. As comfortable as it is safe, this material has many helpful uses and stylish qualities.